This invention relates to an excavating and pipeline installation system, and more particularly to an excavating and pipeline installation system which continuously excavates a pipeline trench, inserts the pipeline therein, and refills the pipeline trench.
Typically, the installation of a pipeline beneath the surface of the earth involves a multi-step process, requiring several machines, a number of operators and a considerable amount of time. The pipeline sections are first laid out over the surface and are interconnected to form a pipeline string. A pipeline receiving trench is then dug using any of various machines. The excavated material is piled along one side of the trench, thereby increasing the total right-of-way space needed to install the pipe. Using a crane or other lifting devices the pipeline string is then lifted from its assembly location into the pipeline receiving trench. The pipeline trench is then refilled with the excavated material using a bulldozer or the like to push the material back into the trench after which the excavating site is graded. The process thus involves handling the pipe and excavated material several times during the installation of the pipeline.
The present invention comprises a novel excavating and pipeline installation system which overcomes the disadvantages that have characterized the prior art. Thus, the preferred embodiment of the invention comprises a system capable of continuously excavating a pipeline receiving trench, continously positioning the pipeline within the excavated trench and continously redepositing the excavated material into the trench. The system thereby requires a minimum right-of-way for installation of a pipeline and is capable of installing the pipeline in a relatively short period of time.
In accordance with the broader aspects of the invention, an excavating and pipeline installation system comprises a vehicle, and an excavating wheel assembly for excavating a pipeline receiving trench at a predetermined location beneath the surface of the earth. The excavating wheel assembly is connected to the front end of the vehicle for engagement with the material to be excavated. Structure is provided on the vehicle for positioning the pipeline directly above the predetermined location and for positioning the pipeline within the pipeline receiving trench. A main conveyor is mounted on the vehicle for transporting the excavated material rearwardly and upwardly from the excavating wheel assembly to the rear of the vehicle. The system further includes a plurality if detachable trailers for connection to the rear of the vehicle. Each trailer includes a conveyor for receiving the excavated material from the main conveyor and for transporting the excavated material to the rear of the vehicle and to the rear of the trailers, whereby the excavated material is ultimately redeposited into the pipeline receiving trench.
In accordance with the more specific aspects of the invention, the vehicle comprises a main frame which is supported by a plurality of tired wheels at the rear end of the frame and a plurality of track-type wheels at the front end of the frame. A subframe is mounted on the main frame for pivotal movement about the axis of the tired wheels, and the excavating wheel assembly is rotatably supported on the subframe. The subframe also supports the main conveyor for receiving excavated material from the excavating wheel assembly and for transporting the excavated material to the rear of the vehicle. Bolster rollers are mounted on the supporting structure for initially lifting the pipeline, the pipe rollers are mounted on the main frame for exerting a downwardly directed force on the pipeline in order to insert the pipeline into the receiving trench. The plurality of detachable trailers are supported by a plurality of tired wheels located centrally between the front and rear end of the trailer. The location of the plurality of wheels permits the plurality of trailers to move around a curved path.